In prior art otoscopes having their own light sources, problems with the quality of the illumination have always existed to a greater or lesser degree. Thus, in order to illuminate a field at the distal end of the viewing passage, it has been customary to position the lamp in the viewing passage as disclosed by U.S. Pat. Nos. 1,849,701 and 2,797,684 both owned by the assignee of the present invention. Unfortunately, with the lamp in this position, if it is large enough to provide as much illumination at the field of view as might be desired, it becomes an objectionable obstruction in the viewing passage. On the other hand, if a small lamp is employed to minimize the obstruction, there probably will be insufficient light at the field.
A solution to the problem just mentioned is to remove the lamp from the otoscope viewing passage altogether as disclosed in U.S. Pat. Nos. 3,373,737 and 3,698,387. These patents are also owned by the assignee of the present invention and represent the closest prior art known to the applicants. In the otoscope shown in each patent the lamp is located in the base of the instrument and optical fibers that are molded into the instrument head and speculum transmit the light from the lamp to the distal end of the speculum.
The fiber optic otoscopes just described have excellent performance for most applications and have been well received by the medical profession. There are, however, a number of physicians who still prefer the traditional, metal diagnostic and operating otoscopes as shown in U.S. Pat. Nos. 1,849,701 and 2,797,684, respectively. These instruments are more rugged than the molded plastic instruments and therefore are likely to have a longer, more trouble-free life. The metal otoscopes are at the same time less expensive than molded plastic instruments of the type shown in U.S. Pat. No. 3,698,387. Other reasons the traditional, metal otoscopes are preferred by some physicians are that their specula do not require added tip extensions, and they are well adapted for use with veterinary specula which the fiber optic otoscopes are not. It is an advantage also that the metal otoscopes can be used with their specula removed altogether which cannot be done with the fiber optic type and may be desirable under certain circumstances.